Create first robot-account during workflow creation

[migmartri]

Usuallym the steps required to create and use a workflow are

Create a workflow chainloop wf create

$ chainloop wf create --name test --project test
┌──────────────────────────────────────┬──────┬─────────┬─────────────────────┬────────┬─────────────────┐
│ ID                                   │ NAME │ PROJECT │ CREATED AT          │ RUNNER │ LAST RUN STATUS │
├──────────────────────────────────────┼──────┼─────────┼─────────────────────┼────────┼─────────────────┤
│ 71de5436-ef9e-4f27-99c6-a67826f7c0a5 │ test │ test    │ 24 Apr 23 14:09 UTC │        │                 │
└──────────────────────────────────────┴──────┴─────────┴─────────────────────┴────────┴─────────────────┘

Create a robot account pointing to that workflow ID

$ chainloop wf robot-account create --workflow 71de5436-ef9e-4f27-99c6-a67826f7c0a5
┌──────────────────────────────────────┬──────┬──────────────────────────────────────┬─────────────────────┬────────────┐
│ ID                                   │ NAME │ WORKFLOW ID                          │ CREATED AT          │ REVOKED AT │
├──────────────────────────────────────┼──────┼──────────────────────────────────────┼─────────────────────┼────────────┤
│ f1f5cc7d-c7eb-4e84-ae45-3b1437d062a6 │      │ 71de5436-ef9e-4f27-99c6-a67826f7c0a5 │ 24 Apr 23 14:09 UTC │            │
└──────────────────────────────────────┴──────┴──────────────────────────────────────┴─────────────────────┴────────────┘

Save the following token since it will not printed again: 

 eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.REDACTED-I

This task is about by default, create a token as well, unless an optional flag is set that prevents that, i.e --skip-robot-account-create

We need to decide where to implement this, server-side or client-side. My gut tells me, based on the limited information we have, that there is no enough data to corroborate that such a change should be implemented by default in the server. So I am leaning towards a client side implementation of it (although automatic contract creation happens server side)